The goal of this project is to investigate the role of the Wnt signaling pathway in zebrafish neural cres development. Because the neural crest has been shown to be critical for normal embryogenesis, understanding the molecular control of cell determination in this cell type is important in the analysis of particular human diseases as well as general control of cell determination. The expression of a downstream component of the pathway, beta-catenin, will be analyzed at a single cell lived by in immunohistochemistry to determine whether neural crest cells respond to Wnt signals in vivo. Following this analysis, gain and loss of function experiments will be carried out in neural crest cells by using single-cell mRNA injection to produce targeted gene misexpression. An analysis of the fate of individual misexpressing cells will be used to ascertain the effects of the Wnt pathway on their development.